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OR-Tools
8.2
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The class for constraints of a Mathematical Programming (MP) model.
A constraint is represented as a linear equation or inequality.
Definition at line 1178 of file linear_solver.h.
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const std::string & | name () const |
Returns the name of the constraint. More... | |
void | Clear () |
Clears all variables and coefficients. Does not clear the bounds. More... | |
void | SetCoefficient (const MPVariable *const var, double coeff) |
Sets the coefficient of the variable on the constraint. More... | |
double | GetCoefficient (const MPVariable *const var) const |
Gets the coefficient of a given variable on the constraint (which is 0 if the variable does not appear in the constraint). More... | |
const absl::flat_hash_map< const MPVariable *, double > & | terms () const |
Returns a map from variables to their coefficients in the constraint. More... | |
double | lb () const |
Returns the lower bound. More... | |
double | ub () const |
Returns the upper bound. More... | |
void | SetLB (double lb) |
Sets the lower bound. More... | |
void | SetUB (double ub) |
Sets the upper bound. More... | |
void | SetBounds (double lb, double ub) |
Sets both the lower and upper bounds. More... | |
bool | is_lazy () const |
Advanced usage: returns true if the constraint is "lazy" (see below). More... | |
void | set_is_lazy (bool laziness) |
Advanced usage: sets the constraint "laziness". More... | |
const MPVariable * | indicator_variable () const |
bool | indicator_value () const |
int | index () const |
Returns the index of the constraint in the MPSolver::constraints_. More... | |
double | dual_value () const |
Advanced usage: returns the dual value of the constraint in the current solution (only available for continuous problems). More... | |
MPSolver::BasisStatus | basis_status () const |
Advanced usage: returns the basis status of the constraint. More... | |
Protected Member Functions | |
MPConstraint (int index, double lb, double ub, const std::string &name, MPSolverInterface *const interface_in) | |
void | set_dual_value (double dual_value) |
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Definition at line 1287 of file linear_solver.h.
MPSolver::BasisStatus basis_status | ( | ) | const |
Advanced usage: returns the basis status of the constraint.
It is only available for continuous problems).
Note that if a constraint "linear_expression in [lb, ub]" is transformed into "linear_expression + slack = 0" with slack in [-ub, -lb], then this status is the same as the status of the slack variable with AT_UPPER_BOUND and AT_LOWER_BOUND swapped.
Definition at line 145 of file linear_solver.cc.
void Clear | ( | ) |
Clears all variables and coefficients. Does not clear the bounds.
Definition at line 122 of file linear_solver.cc.
double dual_value | ( | ) | const |
Advanced usage: returns the dual value of the constraint in the current solution (only available for continuous problems).
Definition at line 136 of file linear_solver.cc.
double GetCoefficient | ( | const MPVariable *const | var | ) | const |
Gets the coefficient of a given variable on the constraint (which is 0 if the variable does not appear in the constraint).
Definition at line 90 of file linear_solver.cc.
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Returns the index of the constraint in the MPSolver::constraints_.
Definition at line 1246 of file linear_solver.h.
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Definition at line 1243 of file linear_solver.h.
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Definition at line 1242 of file linear_solver.h.
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Advanced usage: returns true if the constraint is "lazy" (see below).
Definition at line 1225 of file linear_solver.h.
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Returns the lower bound.
Definition at line 1210 of file linear_solver.h.
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Returns the name of the constraint.
Definition at line 1181 of file linear_solver.h.
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Definition at line 1299 of file linear_solver.h.
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Advanced usage: sets the constraint "laziness".
This is only supported for SCIP and has no effect on other solvers.
When laziness is true, the constraint is only considered by the Linear Programming solver if its current solution violates the constraint. In this case, the constraint is definitively added to the problem. This may be useful in some MIP problems, and may have a dramatic impact on performance.
For more info see: http://tinyurl.com/lazy-constraints.
Definition at line 1240 of file linear_solver.h.
void SetBounds | ( | double | lb, |
double | ub | ||
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Sets both the lower and upper bounds.
Definition at line 127 of file linear_solver.cc.
void SetCoefficient | ( | const MPVariable *const | var, |
double | coeff | ||
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Sets the coefficient of the variable on the constraint.
If the variable does not belong to the solver, the function just returns, or crashes in non-opt mode.
Definition at line 96 of file linear_solver.cc.
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Sets the lower bound.
Definition at line 1216 of file linear_solver.h.
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Sets the upper bound.
Definition at line 1219 of file linear_solver.h.
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Returns a map from variables to their coefficients in the constraint.
If a variable is not present in the map, then its coefficient is zero.
Definition at line 1205 of file linear_solver.h.
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Returns the upper bound.
Definition at line 1213 of file linear_solver.h.